Photometric Assay of Plasma Heparin.

Abstract

A photometric assay of heparin Na is descr. This con. sists of a preliminary precipitation of 5 ml. of plasma with n-octylamine, reprecipitation with Zn(OH)2, decomposition of this precipitate with phosphate buffer soln., and final precipitation with toluidine blue. After washing, the red-purple residue is taken up in alkaline alcohol and read photometrically. The heparin is a component of the red-purple dye precipitate. Normal plasma contains non-active heparin-like substances, amounting to 0.02 to 0.54 mg.%. Added heparin Na to plasma is quantitatively recovered. Intraven. heparin Na and "depo-heparin" levels follow the clotting inhibition effects. Normal urines contain from 3-12 mg.% of non-active metachromatic substance expressed as heparin Na. Heparin Na added to urine may be recovered.